An Evil Looking Seed from Yonkers

Trapa natans L. the Eurasian water chestnut

I love a good mystery and sometimes this job delivers. A visitor who had been to New York a week before superstorm 'Sandy' found this on the shore of the Hudson river near Yonkers. This is one of the strangest seedpods I've seen in a while (I was assuming it was the seed or seedpod of something that had floated to its final resting place there on the shores of the Hudson). Now I've had strange floaty seeds brought into my office before but this one took the cake. It had a distinctly evil looking appearance (at least by Disney villain standards where most villains have a pointy chin and ears). After typing in such esoteric terms as 'litoral trigonal capsule' and many other permutations of the same into Google with no luck at all I typed 'seeds washed up on a shore' and there it was, the third picture in the image results from Google.  Sometimes it pays to keep it simple, even in botany. Turns out it was Trapa natans, also known as the Eurasian water chestnut, a plant that is an invasive water weed that ranges from Virginia to Vermont.